In DTP using computers, data to be edited is displayed on a display device, and layout and typesetting operations (i.e., character typesetting) are performed on this data based on user input. In typesetting operations, “gyookuri” (leading in European-language typesetting), which is the relative positional relationship between a plurality of lines, is set. Leading is the distance between a line and the next line when the line is displayed or printed, and thus corresponds to the distance from one line's reference point to the next line's reference point. Therefore, leading includes one line's “line height” and the “spacing amount” (i.e., interline spacing) between that line and the next line.
However, there are situations in which the character data to be edited is not just Japanese but also a European language, and there are situations in which the two are mixed together. Therefore a DTP system needs to be capable of processing European languages as well as Japanese, and to handle documents containing a mixture of European languages and Japanese. When doing so, there are a number of points in which the typesetting rules for European language typesetting and Japanese typesetting differ, so automating DTP typesetting operations has proven to be difficult, and conventional DTP using computers must be processed by many manual user operations. Leading in typesetting operations is an example of a situation in which manual intervention by the user at present is unavoidable, thus making the typesetting operation difficult and complicated.
For example, in European language typesetting and conventional DTP, leading (i.e. “gyookuri” in Japanese) is set as a distance from a current line's baseline to a previous line's baseline. That is, as shown in FIG. 7A, in European-language typesetting two lines included in text frame 31 on the screen of a display device displaying data that is undergoing typesetting are coordinated and positioned on their respective baselines 29 and 30, and distance 32 between the first line's baseline and the next line's baseline corresponds to the leading. Therefore the top side of text frame 31, i.e. the top side of the first line, is offset downward by exactly gap 33 from reference line 28 set in the page.
On the other hand, FIG. 7B shows a case in which Japanese text is assigned inside text frame 35. As in FIG. 7A, this is a case in which the text is positioned according to the European-language baseline. Both examples are 24-point characters, and show a situation in which the result of automatic leading setting is leading (e.g. leading 32 and 36) set to a 29-point dimension. Both text frame 31 and 35 are coordinated on the European-language baseline. Nevertheless, the top side and the bottom side of the text frame 35 in FIG. 7B are vertically offset (e.g. gap 37 and 38) from the top side and bottom side of the text frame in FIG. 7A. In FIG. 7B, unlike the case in FIG. 7A, the top side of the text frame, i.e. the top side of the first line, is coordinated with reference line 34 set in the page.
In nearly all electronic typesetting today leading is set with reference to a baseline, so when the leading value of a current line is increased, for example, that line moves downward inside the text frame and is positioned more distantly from the previous line. Nevertheless, changing the current line's position by changing the leading value setting in this manner is not desirable, particularly in Japanese typesetting, so the user needs to manually correct the vertical position of one or more lines each time the set leading value changes.